@icantbelieveitsnotbutterUSA "You're teeth are so yellow, I can't believe it's not butter!" I know what you're going to say now "ZeroPeroxide.com you can do BUTTER than that!" To which I will reply, "Only MARGARINEly!"

http://safetoothwhitening.org/the-law/The EU thinks that peroxide based whitener are so dangerous, the banned them in 2012. Only very low concentrations (too low to whiten teeth) are considered safe. Your best best for whitening you teeth is to use a product, like Zero Peroxide, whose main ingredient is sodium bicarbonate (baking soda). Instead of harming teeth, it actually helps!